Protective material, lining, edgecover and packing tape.
防护材料，衬里，包边及包装带。
2
We introduced the concept of block directed edgecover diagonal quasi dominant matrix, obtained a new nonsingularity criteria for matrices and distribution theorem on eigenvalues of matrix.
引进了拟块有向边覆盖对角占优矩阵概念，给出了新的矩阵非奇异判定定理和特征值分布定理。
3
So the point on the edge must rotate much faster to cover that 50 in. in 1.8 seconds than the point near the center, which has to cover less than a fifth of the distance in the same time.